


Dragon Heat

by GintaxAlvissforever



Series: Inktober/Kinktober 2019 [6]
Category: Fire Emblem Series, Fire Emblem: Fuukasetsugetsu | Fire Emblem: Three Houses
Genre: Alpha/Beta/Omega Dynamics, Anal Fingering, Anal Sex, Humor, Implied Relationships, Inktober 2019, Jeralt is still overprotective of his son, Kinktober 2019, M/M, Omega Verse, Pre-Time Skip
Language: English
Status: Completed
Published: 2019-10-15
Updated: 2019-10-15
Packaged: 2020-12-31 01:30:13
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,694
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/21035138
Author URL: https://archiveofourown.org/users/GintaxAlvissforever/pseuds/GintaxAlvissforever
Summary: When an unexpected Omega goes into heat, Jeralt fears the worst. Rhea summons him due to the dire situation. While he's glad that it was not Byleth who had gone into heat, the fact he's told by Rhea to fix the person in heat only annoys him to no end.





	Dragon Heat

**Author's Note:**

> Can't count again on the days. Ended up doing the Omegaverse for the first time (I might have done something similar but not really). 
> 
> Byleth is male and Beth is female. 
> 
> Inktober word: “Dragon”

There were two things that Jeralt feared: his children being in danger and not being able to help them or his children being taken advantage of due to their secondary gender. While the former applied to both twins, the latter only applied to his eldest son. Twins were an oddity when it came to secondary genders. Jeralt thought that they would both have the same secondary gender when they reached maturity. Alas, that didn't happen. His daughter, Beth, presented herself as an alpha rather early on, but her older twin Byleth did not present himself immediately. Jeralt assumed that Byleth would have been an alpha as well, but his secondary gender was stunted similarly to his emotions.

Later, Byleth would present himself as an omega. This caused a lot of problems for Jeralt. Most of the mercenaries he led were alphas, some betas, and only two omegas outside of his son. While his son was still an excellent swordsman, being an omega in an alpha pack only made Jeralt more overprotective than he had to be. He decided that Byleth wasn't going to mate until he felt the time was right. Beth joked that this meant "never" for Byleth seeing as how Jeralt couldn't stand the idea of his son being under the arms of another alpha. It didn't matter if it was a friend he knew or someone whom Byleth trusted. For as long as Jeralt drew breath, he wasn't going to let anyone touch his son, much less know of his omega status. Byleth didn't understand what the big deal was and never brought attention to his secondary gender at his father's request. If asked, he simply said he didn't know and have others make assumptions.

Unfortunately, the goddess didn't see eye-to-eye with Jeralt. The fateful encounter with the brats from Garreg Monastery resulted in the Knights of Seiros finding and dragging him back. There, he served as one of them again under Lady Rhea. Twenty years on the run just to end up back in this place was irritating to say the least.

The worst part were the students. All different smells scented the school. Many noble brats were alphas looking for mates to marry along with solidifying themselves at the top of their class. Some nobles were omegas, and they were doomed to be subjected to the alphas if they let their guard down. Most of the commoners here were betas although there were a few exceptions to the rule as secondary genders weren't limited to rank.

The three brats were the worst. They were attracted to Byleth more than Beth and for good reasons. Beth radiated dominance with her alpha scent. Byleth, in contrast, lacked it. If one had a keen sense of smell, they might have been able to whiff the rich omega scent from him. Byleth had a calming fragrance around him similarly to a flower in bloom with a sweet and alluring scent. Jeralt quickly determined that the future empress and future king were alphas with how upfront they were about Byleth teaching their houses. Byleth ended up becoming the teacher of the future Alliance leader because he lacked any defining scent.

That was both a good and bad thing. Claude Von Riegan had yet to present his secondary gender. In a few months, he would reach the mature age of eighteen. It's probably why Claude hadn't been as forceful as the other two leaders, and Byleth went with what he felt was safer. Even the students in the Golden Deer house were rather balanced with two alphas, three betas, one omega, and one unknown. Both alphas weren't dangerous either despite being stuck-up. One alpha was picky about who would be his future wife and the other was too lazy to pick a mate. All good signs of Byleth being safe from them.

But the bad thing for Jeralt was that even if Claude didn't have a secondary gender, the student still fancied his son. If Claude ended up an alpha, there was no doubt his son was doomed. Byleth might not have noticed, but he ended up favoring Claude so no matter what secondary gender Claude presented as, Byleth would be there to help him.

Though it was only one in three chances, Jeralt decided to keep a close eye on the devious student. As it got closer to Claude's birthday at the end of Blue Sea Moon, the mercenary became more agitated. The Goddess Rebirth Ceremony was getting closer so the Knights needed to be on high alert. Jeralt couldn't be in multiple places at once. He just had to trust Byleth.

However, a few days before the ritual, an omega was hit with an intense heat felt throughout the monastery. Jeralt feared the worst.

He wanted to find his son, but Alois needed him to speak to Rhea immediately. The veteran mercenary wanted to give Rhea a piece of his mind. It would be justified too seeing as how the omega scent riled up any and all alphas in the area. The scent was the strongest where the Archbishop resided. Alas, the scent did not come from her. Alois dismissed himself, leaving him alone with Rhea. It was odd not seeing Seteth with her.

"Jeralt, I apologize for calling you so suddenly," Rhea began. Her face contorted into something of distress which Jeralt didn't like seeing. "You probably felt the disturbance."

"Felt? More like took a whiff of it and wished that I hadn't," Jeralt growled. "How in the world did you allow an omega to walk around knowing they were going to be in heat soon?" Jeralt still believed it was Byleth. The sooner he finished his conversation with Rhea, the sooner he could find and protect his son. Rhea was not amused.

"Jeralt, calm yourself. It was not your child who went into heat."

Oh, Rhea would know so much about Byleth. She had taken an immediate liking to him when her eyes laid upon him. The fact that she had tried to be alone with Byleth more times than not set off alarm bells in Jeralt's mind. He could not defy the Archbishop, but he could warn his son to watch his back (which he had been doing a good job of the past couple of months).

"I need your assistance with who it is though," Rhea continued. "Due to circumstances…I cannot help him."

"Him?" Jeralt asked. There weren't that many men close to Rhea. With the limited amount of people, Jeralt put two and two easily. "…Where is Seteth?"

"I confined him to his room," Rhea answered. "He stressed himself out with the Goddess Ritual. I told him that he did not have to fear for my safety. Seteth…didn't take my advice, and as you can see…his heat hit sooner rather than later."

"You mean a week before the ritual," Jeralt corrected. That meant that Seteth would have had his heat at the end of the month when everything calmed down.

"He forced himself to make the necessary preparations. Now I'm put in this situation where the students do not know who is in heat and is triggering their heats as well. I fear more for the other omega students than Seteth. No one knows it is him."

Jeralt understood why Seteth's secondary gender remained ambiguous. The advisor came off as such an intimidating individual that people automatically assumed he was an alpha. An observant person would have noticed that his scent didn't add up. While his little sister Flayn was an obvious omega, it seemed odd that her older brother would be one too. Alas, it just seemed to run in the family.

"Seteth was married once," Rhea mumbled. "Long ago…he has no mate now and suffers during his heats."

"And you want me to fill the role?" Jeralt questioned in an unamused tone.

"I apologize. I know you still grieve for your wife as does Seteth, but I do not have many options. I need him to return to normal as soon as possible. Without Seteth, the students will begin to worry."

"I think the brats are more concerned on who they want to mate with now than the actual ritual," Jeralt told her as a matter of fact statement. "While I'm glad to know it's not my son, I still wonder how you intend to explain what happened."

"I do not like the idea of using Flayn as a scapegoat, but in this situation, it will have to do."

"And where is Flayn now?"

"She is waiting for you outside of Seteth's room."

Jeralt had no choice. It was better to get things over with before other people started questioning what was going on. Alois wouldn't let him hear the end of it, that's for sure. He also didn't want Beth to get wind of this.

"Fine. It's not like I have a choice anyway."

Rhea smiled. "I am forever grateful."

* * *

Jeralt always found it odd how outside of Rhea, Seteth and Flayn shared the third floor with her. He could think of many reasons why this was the case judging from their hair color, but he dared not voice his concern. Right now, he needed to help the Archbishop's aid before the situation got worse. Without the stern man, it would be harder to get things together before the Goddess Ritual. Seteth was Rhea's right-hand man after all.

Flayn was waiting for him on the third floor. Her distressed look only made Jeralt want to hurry up and finish this task. As he approached her, she flinched from his presence. He didn't mean to startle her, but he had to remember that his aura often scared others away regardless of secondary gender.

"Sir Jeralt?" Flayn asked in an unsure tone.

"That's me. Reporting for duty," Jeralt grunted. "Lady Rhea wanted me to take care of your brother. Will you let me through?"

Flayn didn't exactly have a choice in the matter. Her frown deepened at what she was told.

"Oh…will everything be okay?" she asked. "My brother usually doesn't have heats like this. He's usually prepared in advance so I fear that something bad will happen."

"Nothing bad will happen," the mercenary reassured the young girl. "I may not look it, but I'm gentle toward others."

Unfortunately, Flayn was a rather gullible young girl. Even if what Jeralt said was true, she shouldn't take what he said to face value. Flayn moved out of the way of the door, allowing Jeralt access to the room.

"Please be careful. My brother is not like other omegas," Flayn warned him. "He has a bad habit of lashing out before he calms down."

Jeralt nodded in acknowledgement. Seeing as how he seemed to have heeded her warning, Flayn quickly left. He assumed that once he arrived that the young girl was to go back to Rhea and wait for things to calm down. The mercenary only creaked the door open and a saintly aroma accompanied with some growling overpowered his senses. He growled as he tried his best not to lose himself right there. He took a slow step inside and made sure to close the door behind him.

Jeralt already started loosening his clothes and armor the moment he stepped inside. He knew what this process implied. Clothes got in the way of the mating process. Although, he would only do the bare minimum for Seteth with the information Rhea gave him. The sound of armor falling to the ground caused Seteth to stop his growling.

It was funny. Jeralt was used to omegas squealing and crying for their alpha partner. Not Seteth. He growled like an alpha as if he was trying to send someone away that he didn't trust. Yet, the sight before the veteran mercenary was captivating. Seteth always came off as a stick in the mud when next to Rhea, who wasn't all that serious. Seteth wasn't around when Jeralt was Rhea's best knight, so he didn't know what to expect.

Seteth already made his nest. It was rough around the edges. If Jeralt were to describe the nest, it felt like a dragon's nest. Approach if you dare. Jeralt had no choice in the matter. Not only was it because of Rhea's request but also because his alpha instincts roared at him to do so.

"Why…are you here…" Seteth hissed.

_He can still talk?_ Jeralt asked himself. It made sense that Seteth hadn't lost himself. He had heats without his wife for so long that he should have been able to communicate during those times.

"Lady Rhea sent me to take care of you," Jeralt answered. "It is rather inconvenient when the Goddess Ritual is going to happen soon, and you're stuck in this heat."

"These heats…don't last…long…" Seteth growled. Jeralt noted how much sweat had already accumulated over his forehead. "I have dealt with this…on my own…don't…need an alpha."

"You say that, and yet you ended up giving into your heat around the students."

"T-That's…"

Jeralt didn't appreciate that way of thinking, but he was at his wit's end. "Why else would you allow other students the pleasure of sniffing your aroma? Did you want to get jumped that badly after years without someone to satisfy you?"

Jeralt blamed his alpha attitude for those words. He approached Seteth's bed. The Archbishop's aid flinched at eth alpha's close proximity.

"Watch your tongue," Seteth snapped, "when my heat…is done…don't think…I won't…overlook this…"

"When your heat is done. But until then, I will help you."

Seteth didn't have a choice. It was Rhea's orders. Still, Jeralt didn't jump on the other man immediately. He wanted to make one thing clear to him.

"Bite or no bite?" Jeralt questioned. "I'm about to make an absolute mess of you, but I will respect your wish."

Despite saying that, Jeralt was already on the bed. Seteth still had time before it was too late to take anything back.

"No biting," Seteth muttered. "And…I would appreciate…it if you…did not…knot inside…"

The second part was going to be difficult. Jeralt hadn't had a mate in a while either, so he doubted he would be able to keep that promise. If he didn't bite, then this arrangement should be fine.

"Can't promise that second one. You are looking too good to eat."

God, that sounded embarrassing. His children wouldn't appreciate that sort of language one bit.

Not like that mattered now. Jeralt immediately seized Seteth's chin and pressed their lips together. Perhaps he was moving too fast for Seteth's liking as the other man didn't respond immediately. The veteran mercenary worked his hands underneath the advisor's top. Seteth only removed his cape, pants and boots. The shirt and underwear remained on for whatever reason. Either he gave up mid-strip, or he tried to maintain his dignity.

Jeralt pulled back waiting to see Seteth's reaction. Red suited the Archbishop's aid's face.

"Gnn…don't…fore…play…" Seteth whined. "Hurry…up…"

While he tried to maintain some sanity, Jeralt wanted to see him crumble. Again, he pressed his lips against Seteth's, and this time the omega opened his mouth for the alpha. It seemed that not having a partner for years hindered how well Seteth was at kissing. He was still a holy man to an extent so it felt invigorating being able to control him.

"Mmm…mmmph…"

Seteth tried to say something. Jeralt's eyes looked down past the shirt and the boxers. He smirked into the kiss. Seteth's eyes widened now that large hands went from touching his chest to touching his underwear.

The mercenary pulled away again, causing Seteth to whine at the loss.

"What's the matter? Did you wet yourself thinking of an alpha taking you?"

Seteth had no snarky retort. He weakly eyed the alpha who rubbed his hand against his boxers. A wet spot ruined the underwear, and it wasn't just from the front. Jeralt dug his hands deeper and checked the rear.

The self-lubrication already happened. Seteth had tried so hard to hide it with his clothes but it only took strong hands to pull down his boxers to see the lubricated hole.

Jeralt noticed that despite being an omega, he lacked the genitals needed to reproduce. Maybe years of not having a partner resulted in the disappearance. Rhea was capable of messing with people's bodies, so in the back of Jeralt's mind, he wouldn't be surprised if she did something to her aid as well.

"Look at this perverted hole," Jeralt hummed. "It's yearning for an alpha."

Seteth whined at Jeralt's words. It was so easy for the mercenary to stick his finger into the hole. The squelching noises only made Jeralt move faster. He inserted a second finger almost immediately. Seteth gasped moving his hips to push the alpha's fingers toward his prostate.

At this point, the omega couldn't form coherent sentences. He wanted the teasing to stop. He needed an alpha's cock. The scent was too much. He hadn't even done much to him and he was already a mess. He hated this so much. He wanted to scream.

"Please!" Seteth cried. "Please! Gnn! Alpha!"

Omega instincts always won out in the end. Jeralt had forced a third finger in and enjoyed Seteth becoming undone. He squirmed underneath the stronger man, begging, crying, demanding for more. Jeralt only needed to use his other hand to hold Seteth down on his bed. The longer this went, the more Jeralt started to notice Seteth's grip on him tightened. Flayn warned him that he was dangerous, and now he's finally picking up on it.

"You are an impatient Omega."

Jeralt yanked his pants down quickly. He positioned his cock at the wet hole and forced his way in. Seteth's voice broke the moment his body welcomed a cock inside of him. Jeralt wouldn't question if this was Seteth's first alpha male cock. Not waiting for the Archbishop's aid to adjust, Jeralt pounded straight to the sweet spot. Seteth forgot where he was if he was going to be screaming like a commoner.

"Heh…that's it. Omega…" Jeralt growled possessively. "Haven't had a good dick like this in a while, huh?"

How was Seteth a holy man with the way he moved his hips in rhythm with the alpha partner Rhea chose? If Seteth was this open during his heat, Jeralt wouldn't mind helping this man more often. Everything about the man was so odd…and yet comforting. A part of Jeralt thought that Seteth for a moment reminded him of his late wife.

The thought alone brought Jeralt back to reality and-oh, was he going to cum already?! Well, it was just one round, but he didn't expect to be close already!

"Nmmmm…innnns…gnn…"

Seteth tried to remind him about not cumming inside of him. Despite being lost in his lust, he still tried to remind his temporary mate about the rule. Unfortunately, there wasn't enough time. If he tried to pull out now, the omega wouldn't get any of the cum he desperately needed. And Jeralt wanted to see the face he made as he came inside the other man.

Jeralt didn't feel the least bit apologetic when he came inside of the omega. He wasn't knotting, but he was still marking his territory. He was going to fill this prideful man up and put him in his place. Seteth squirmed underneath him, and oh did he look good being taken apart like this. He kept it together up to this point, but now he was crying out his orgasm. Jeralt felt the omega taking all the semen out of his cock like a champ. It had been so long since an omega had been this needy.

How long was it before they both finished their orgasms? One round wasn't going to be enough for either of them. Jeralt regained his sanity for a quick minute. He licked his lips seeing Seteth panting like a pathetic dog.

"Not bad…" Jeralt praised. "You held out for a while."

Seteth weakly glared as a response. "I'm old…but not that old…"

"And your omega self is telling you to keep going."

"My bones…"

Jeralt chuckled. It wasn't everyday that he could have a casual chat like this. Seteth could take him multiple times. He wouldn't faint anytime soon. He wasn't human…

"If you can complain, then you can handle getting the heat fucked out of your sexy body."

Before Seteth could argue, Jeralt started pounding into him again. It was a good thing Flayn had already left the floor. Her brother's voice could be heard from outside and it was something that Seteth didn't want to be reminded of when all was said and done.

* * *

Seteth recovered rather quickly once Jeralt bit him. He didn't want to talk about it and used the Goddess Ritual as the main excuse to not address the incident, but Jeralt knew better. It was all business. It's not like Seteth would just give up his love for his dead wife for someone else in proximity.

Dealing with Seteth meant Jeralt could now focus on his duty and his son. For all the random heats (and people finding their significant others), Byleth remained as stoic as ever. Beth was agitated by the strong smells, but she didn't jump anyone either, so Jeralt counted that as good.

So many things occurred in the span of a couple of days. The people of the Western Church were taken in and executed without a trial. The knights could relax again despite being put on outside missions. The most important thing was that Claude's birthday passed, and he still didn't present his secondary gender. If Claude didn't present last month, he wasn't going to present for another couple of months.

That's what Jeralt wanted to think. However, the moment Byleth got assigned a new mission, he noticed there was a very powerful scent in the Golden Deer room. It didn't belong to his son, so that meant one thing.

"Oh, you have got to be kidding me…"

**Author's Note:**

> Done with 4130 words. Notes!
> 
> So, in this universe, Jeralt's overprotectiveness of Byleth stems from him being an omega unlike his sister who is an alpha. Byleth won't talk about his second gender and hides it with a scent suppressor. I should make a note on who are the A/B/O. I should also make a mental note that most commoners end up as betas because they don't have a special bloodline.
> 
> Alpha: Beth, Jeralt, Edelgard, Dimitri, Ferdinand, Sylvain, Dedue, Lorenz, Hilda, Rhea, Catherine, Gilbert
> 
> Beta: Dorothea, Petra, Caspar, Mercedes, Raphael, Ignatz, Leonie, Alois, Shamir, Hannaman, Manuela
> 
> Omega: Byleth, Bernadetta, Marianne, Ingrid, Felix, Linhardt, Annette, Ashe, Flayn, Seteth
> 
> Not Presented: Claude (late bloomer), Hubert (combination of late bloomer and trauma), Lysithea (experiments messed up her second gender), Cyril (child)
> 
> 2\. I always assumed that Jeralt is the one person outside of Seteth and Flayn who could speak casually to Rhea without pissing her off. Seteth and Flayn are family so it makes sense. I also believe that Rhea truly cares for Jeralt as a friend, but her obsession with her mother led to her hurting him. It's why I feel she didn't question Jeralt where he went for twenty years to make up for what she did to his wife.
> 
> You can decide what secondary gender Claude is. I'm personally leaning toward omega due to the smell but Jeralt's reaction leans toward alpha. I left it ambiguous for the laughs.


End file.
